Control mechanism



March 27, 1934. H. F. SMITH 1,952,515

CONTROL MECHANISM Filed Nov. 3, 1927 3 Sheets- Sheet l NVE/ V TOR. 2. MBY ATTORNEYS.

March 27, 19(34. H, F SMn-H 1,952,515

CONTROL MECHANI SM Filed Nov. 5, 1927 3 SheetsfSheet 2 START INVENTOR.

cau) LQQ.. TTORNEYS.

March 2 7, 1934.

H. F. SMITH CONTROL MECHANI SM Filed NOV. 3. 1927 3 Sheets- Sheet 3 Il?-:l

Ilig- E IN V EN TOR.

Hwy/4M A TTORNEYS.

Patented Mar. 27, 1934 UNITED STATES PATENT OFFICE assignments, to C.,F. Kettering, Inc., Dayton, Ohio, a corporation of Delaware Originalapplication Becember 14, 1925, Serial No. 75,316, now Patent No.1,823,332, September 15, 1931. Divided and this application November 3,1927, Serial No. 230,881

Claims.

This invention relates to electrical control appara-tus, and moreparticularly to switch mechanism.

One of the principal objects of the invention is 5 to provide controlmechanism responsive to varying pressure conditions to effect electricalcontrol.'

Still another object or the invention is to provide a switch mechanismwhich is non-arcing during use.

Other features, objects and advantages of the invention will be apparentfrom the description and claims set out below, and the accompanyingdrawings.

In the drawings in which like characters of reference designate likeparts throughout the several views thereof;

Fig. 1 is a vertical sectional view with parts in v elevation, showingparts of the electrical con- 2Otrol apparatus including the switchmechanism, as applied to the control of an electrically driven blower;

Fig'. 2 is a vertical sectional view, at rightangles to Fig. l', takenalong the line 2--2 of Fig'. 1";`

Fig. 3 is 'a view diagrammatic in character of the blower and controlmechanism, and comprising a wiring diagram of the control mechanism; l

Fig. 4 is an enlarged somewhat diagrammatic elevational view showing oneelement of the control mechanism;

.,Fig. 5 is a vertical sectional view similar to Y Fig. l and showing amodification thereof;

' Fig. 6 is a diagrammatic view similar to Fig. ,Bbut` comprising theform of control mechanism shown in Fig. 5`; and

I Fig. 'l is a diagrammatic view of still another somewhat modified formof control.

` 40 For purposes of clearer description. this inven tion is illustratedinconnection with an electrically operated blower forming part of asystem for generating, and delivering to a place oi use, a combustiblegas-such as producer gas. Tflowever, this is by way of illustration andnot by way of necessary limitation. The switch mechanism of thisinvention is not at all so limited in its applicability, which isgeneral. For example, it/I is peculiarly well adapted for use withelectric signs, because of its non-arcing characteristics which lea'veit free from objectionable interference with radio'reception.

This casefisa division of the copending applicationof .Harry 11E-Smith',Serial No. 75,316, filed (Cl. Uli-375) December 14, 1925, now Patent No.1,823,382, is sued September 15, 1931.

In the embodiment shown in the drawings, the blower or pump which is ofthe centrifugal type, is indicated at 25. This blower may be of anyconventional character but very satisfactory results have been securedwith a blower of the character generally shown in the drawings, whichblower comprises a centrifugal fan or impeller having radial bladesrevolving in a volute casing. This blower is driven by a suitableoperating or driving means illustrated as an electric motor 26, theblower being preferably in driving connection with the motor armatureshaft; and associated therewith is control apparatus for governing theoperation of this blower in a predetermined manner by control of theelectric motor 26 driving this blower. As shown herein the blower isconnected to the generating chamber of a gas producer (not shown andwhich may be oi any suitable construction) to draw a blast of air andmoisture through the incandescent fuel bed within the generating chamberthereof to produce combustible gas, the blower delivering thiscombustible'gas under pressure to a suitable delivery main. Thegenerated combustible gas withdrawn from the producer is generally iirstcooled and then purified before it passes to the blower. As shown inFig. 3, the inlet pipe of the blower 25 is adapted to be connected tothe purier to receive the cooled and purified gas. The outlet Li0 of theblower 25 is connected to a valve casing 5l which serves to control thedelivery of the generated gas under pressure to either a vent pipe 42 ora delivery main 2'?, the latter leading to suitable work devices adaptedto utilize the general gas, such as gas stoves, the burners of hot-watertanks, gas grates or other gasutilizing apparatus. y

The gas drawn from the purifier by the blower is forced from the blowercasing through the outlet pipe 40, under any desired pressure, thepressure ordinarily in household use being only a few inches ci water.Associated with this outlet pipe is suitable control valve mechanism bymeans or" which it may be connected either to the delivery pipe 2'? orto the vent pipe (l2. Normally, when the plant is not in operation thisvalve mechanism is positioned to close the delivery7 line and to connectthe outlet of the producer to the vent pipe. 1i a producer is operatedcontinuously it will of course furnish combustible gas continuously butthis tends to unnecessarily increase the cost of operation since whennone of the work devices are in use the generated l plant may beeifected an gas would wasted to atmospher Consequently thegas-generating system is adapted for what may be called intermittentoperation in that the plant operates to generate gas, generally, onlywhen gas is being used at a work device. Consequently if the plant hasbeen ing idle-standing by as it is called, it may be necessary to blastthe fuel hed at a comparatively rapid rate for a brief period in orderto bring it up to good gas-making condition. Euring starting or theplant, during any such blowing-up period, the blow should be connectedto a vent, as otherwise e products of the combustion during the bloing-up period would be forced into the house. Generally the gas produceror generator will be located in the bosement of the house, or in someouthoirse, while t work devices, such as the stove7 the hot-wateil tank,the gas grates and the like, will 'be located in the living quarters ofthe house; that the ygenerator and the work devices may be located manyfeet apart. This invention not only provides control mechanism for thevalve which oon-- nects the blower to the vent or to the house line, butin addition provides suitable control mechanism whereby operation of thegas-generating controlled from a distant point, such for instance as asuitable ccntrol switch 45 located at the kitchen stove, or some similarplace, such control being hereinafter termed remote control. In actualpractice this switch is preferably attached directly to the manifoldalong' the i1 ont of the stove, within which are located the variousindividual burner valves which control operation oi the stove.

The outlet pipe .40, of the blower is attached to the inlet opening 50,of the valve casing 51,

which casing is divided by an upstanding circular partition 52 into twocompartments 53 and 54. The compartment 53 is connected through theinlet openinfr 50 to the outlet fl0 of the blower, the compartment 54being connected througlfi the restricted opening 55 to the housedelivery line 27. Inasmuch as the centrifugalblower delivers a definitemaximum pressure at maximum operating speed the restricted opening 55determines the maximum amount of gas which may pass into the house lineduring operation. Positioned within the compartment 54 is opstandinghollow guide 58, which has slidably mounted therein the stem 59 of thedisc valve 60, which valve is adapted in one position to seat upon theupper edge of the partition 52. The upper end of the casing 51 is open,and is attached, in gastight connection, to the lower end of the casing65, which has an opening or passage 56 "n the lower face thereorh whichopens into the open upper end of the casing 5i. This opening 66 isprovided with downwardly extending :dange or seat 57, adapted tocooperate with the upper face of the valve 60. This open casing 65 achamber 68 therein, which connected to the passage 65. This chamber 68also connected by means of the passage 59, with the vent f 42.Positioned within the chamber 68 is c tromagnet designated generally bythe numeral 75, which comprises generally a spool-shaped core 76, havinga suitable winding '.77 thereon, this magnet being adapted whenenergized to lift the valve 60 against the seat 6'? to close connectionbetween the inlet passage 50 and the vent pipe 42. When the magnet isnot energized the weight of the Valve 60 causes it to seat against 'theupper edge of the partition 52, thus opening connection between inletopening 50 and the producer;

vent pipe 42 and closing connection between the inlet opening 50 and thehouse line 27. When the valve is held in uppermost position and againstthe seat 67 the inlet passage 50 is disconnected from vent and isconnected to the house line 27, so that gas under suitable pressure isfed to that line. Within the passage 69 is a restricted opening 70 whichfunctions with respect to the vent pipe just as does the opening 55 withrespect to the house line.

For effecting the desired control of the gas generation the switch 45may be made .as a threebutton switch, as shown diagrammatically in Fig.3. This switch in practice is preferably of the press-button type, andeach button opens or closes contact through a line switch. As showndiagrammatically in Fig. 3 there is a switch 80, which is used to closethe proper circuits to cause the blower to start operating to blast thea second switch 81 which is adapted to switch connection of the producerfrom the Vent pipe to the house line after the blowingup operation hasproceeded long'enough to properly condition the active zone of the fuelbed; and a switch 82 which stops operation of the blower and therebyshuts down the plant.

When it is desired to start the operation of the producer, presumingthat it has been standing by, or that it is starting from cold and thefire is being freshly kindled therein from burning paper or the lil-:eplaced in the ash-pit of the producer, the button 8O is pressed to closethe switch associated therewith. One pole of this switch is connected.by means of the conductor 84 to one terminal of the battery 85 or to anyother source of electrical energy. If desired the electrical controlsmay be arranged to plug into the ordinary household electric line, withthe use of suitable conventional transformers. It is only needed,therefore, that the switch S0 have one pole thereof attached to thesource of electrical energy. The other pole is connected by means of theconductor 86, to one erminal or an electromagnet 87, the other terminalof which magnet is connected by means of the conductor 88 to the otherpole of the battery 85, or other source of electrical energy. Closingthe switch energizes the magnet 87 and this in turn attracts thearmature 90 which is pivotally mounted adjacent the end of the core ofthe magnet 87. One end of this armature 90 is connected to one side 91of the house-lighting line, the other end being provided with a contact92 which cooperates with a corresponding contact 93, the contact 93being connected by means of the conductor 94 with an electrode 95. Thiselectrode is positioned within a suitable container 100, preferably ofglass, which container comprises an inverted tube, closed at the top,within which the electrode 95 is mounted, and open at the bottom, thebottom extending down into a glass container 101, which is supportedupon the top of the casing 65. This container .holds a considerablequantity of electrolyte or" any suitable character which is designatedgenerally by the numeral 102, and the lower open end ofv the tube 100extends to terminate within the electrolyte and below the end oftheelectrode 95. 1n practice it has been found that very satisfactoryresults have been` obtained where this electrolyte consists of verydilute sulphuric acid. A thin layer 103 of paraffin oil or the like ispreferably oated on top of the electrolyte to prevent evaporation. Alsopositioned with the container 101 is a second electrodev 105. BothYthrough the tube 115 and vent 42.

:tacts ..92-93 wconstituting the main .Leading off from the top of thetube 100 is vthe blower.

-.crushed or granulated carbon 106, which serves to greatly increase thesurface area of this electrodeand'thereby serves to insure.. goodelectrical contact between the electrolyte 102 and the electrode .105.This electrode 105 is connected by lmeans of the conductor .110 to onepole of the blower-operating motor .26, the other pole of which isconnected by means of the conductor .111 to the :other side of thehouse-lighting line. The `two electrodesand the cooperatingelectrolytetherefore function as an auxiliary switch or contact memberWithin the motor circuit, the conswitch.

a passage 115 which opens into the inlet passage of the Valve casing.When the plant is not operating the Valve will be positioned upon theseat at the top of the partition 52, with open connection between theinlet 50 and the vent pipe 42. At the same time the pressures inside and4outside ,of the tube 100 will be balanced since the inside Vof lthetube is connected to atmosphere So when the switch is closedto startoperation this will close the circuit through the magnet 87, whichwillswing the armature 90 to close the contacts 92 and 93. `At this timevboth the electrode 95 and :the velectrode 105 will be immersed in theelectrolyte andA consequently the motor circuit will immediately beclosed -to cause operation of Because of the positioning of the valve 60the gases fed from the blower will pass freely through the Venttoatmosphere, the house line remaining closed off from the blower. Solong as' the switch 80 is held closed and the valve 60 remains seated onthe partition 52 with the blower outlet connected to vent the blowerwill continue to operate to blow in the fuel bed.

`Provided in the partition 52 is an orice or passage 120 lwhichconnects-the chamber 53 to the chamber 54, and beneath the valve 60 whenthat valve is seated on the partition 52. Connected to thespace 54within the valve casing is a passage ,125, which leads into the bottomof a chamber i125 within the casing 127, supported above ythe containerl101. Thechamber 126 is provided ,withralexible diaphragm128, of leatheror other :suitable-material, which is held in place by means of asuitable retaining ring 129 and has a weight 130 carried thereon, whichweight tends to urge the ydiaphragm downwardly. Mounted upon the weightis an upwardly extending standard 131 .which is connected to an arm 132which is in turn :attached to the pivoted armature 133, associated withthe electromagnet 134. As pressure tends to build up in the chamber 126below the diavphragm 128 .the diaphragm is raised carrying the weightand larm 132 with it. The free end of the arm 132 has a latch member 135associated therewith whichmoves behind the end of the armature 90,as thediaphragm moves upwardly, to latch that armature with the contacts 92and 93 closed. As soon as this condition is realized the ,operator may`remove his finger from the switch 80 as the motor circuitis .then heldclosed so long as the pressure within the casing 127 is sufficientlygreat to hold the diaphragm up.

When'itis desired to turn the gas from the ven into the house line, `theoperator presses Athe button to close switch 81. This causes energizingof magnet 75, the current flowing from the battery through the conductor84, across the switch 81 along the conductor 138 connected to thatswitch and thence through the winding of the magnet, the direction offlow of the current being as desired. The magnet then lifts the valve 60against the seat 67 to disconnect vthe blower from the vent pipe andconnect it to the house line. The weight and proportions of the valve 60are so arranged that when lifted against the seat 67 it will be heldthere by the normal pressure of the gas.

The blower at its normal rate of operation delivers gas at such a ratethat there is `a ytendency for the pressure in the valve casing tolcontinue to build up. As this pressure increases .it acts through thepassage 115 to affect the pressure existent in the tube 100 upon the topsurface of the electrolyte and forces that electrolyte downwardly andout into the container 101. As the pressure cnntinues to build up theelectrolyte is forced downwardly below the lower end ofvelectrede 95 tobreak the circuit. .Sut due to the adhesion of the electrolyte to thelower end of the electrode as the level of the main body of theelectrolyte falls materially below the end of the electrode that portionin contact with the electrode is retained in contact and its surfacetension then causes a progressive diminution of the cross-sectinn of theextended portion of electrolyte until it is pinched off L-as showndiagrammatically in Fig. 4. As a result the current flow is not suddenlyinterrupted byfquick breaking of contact with the contacts within arcingdistance of each other-but is choked .off as the resistance builds updue to the diminishing crosssection of the conducting portion of theelectrolyte and consequently objectionable sparking evils and otherevils normally attendant upon the breaking of a flowing current are `not:presentjas the current flow is nally interrupted at a flow which issubstantially zero so far asobjectionable results are concerned. Thisaction is `accentuated by forming the lower surface of the electrodesubstantially parallel with the surface of the electrolyte and ofconsiderable extent; and further by adjusting the conductivity of .theelectrolyte so that the necked down or diminished portion below theelectrode offers a rapidly increasing resistance which quickly cuts thecurrent flow to unobjectionable proportions. When constructed asdescribed and used with an electrolyte which wets the electrodes therewill .be Ia drop or film of the electrolyte left on the lower end of theelectrode after break, and as the elec'- trolyte rises again intocontact with the .drop the surface tension effects will causesubstantiallyimmediate spreading of the electrolyte into contact withthe whole end of the electrode to give immediately a full, lowresistance contact. However, the relative arrangement and proportioningof the parts is such that the pressure at this time is stillsufficiently high to hold the latch 135 up to maintain the contacts 92and 93 closed, and to hold the valve 60 against its seat 67. As thepressure in the delivery line rises, therefore, above a predeterminednormal the current in the mot Jr circuit is interrupted; 'and as thepressure falls the motor circuit will be again closed` as soon as theelectrolyte comes in Contact with the electrode 95. Thusa continuouslyintermittent energizing ofthe operating motor will occur during use ofthedevice, under vnormal gas-using operations the current to the motorand operation of the blower being normally interrupted a number ci'times a minute with the result that the effective pressure in thedelivery main 27 is maintained substantially constant. In actualoperation the blower' itself generally does not cease movement as it iscontrolled during utilization of the for the contact mechanism isresponsive to slight pressure lluctuations and therefore the breaking ofthe motor circuit as the normal pressure is exceeded is so brief thatinertia will cause continued rotation of the motor and blower parts. Andthe practical effect is to secure a substantially unif arm gas pressure,with a very accurate and simple control for motors of conventionalconstruction and characteristics.

hen it is desired to terminate operation of the device for a period thebutton 82 is pressed to close that switch which completes a circuitthrough the conductors 140, 141 and 84, and battery 85 to energize themagnet 134. This swings the armature to move the latch 135 intoinoperative position and as the magnet 87 is at this time unenergizedthe spring 142 will swing the armature 90 to break the Contact acrossthe contact points 92 and 93 thus stopping the blower. Of course theoperation may also be stopped by cutting off all the burners, or otherwork devices, when the increased line pressure will open the auxiliarycontacts.

In 5 and 6 is shown a somewhat modied form of device. In the ordinaryhousehold use the gas plant may stand idle for considerable periods,overnight for example. Ofttimes the gas is used for heating the water inthe hot-water system in which case there is a continuous load on theproducer and the fuel bed is thus maintained in good gas-makingcondition so that it immediately responds to increased load to give anydesired quantity of good gas within its capacity. But where the producerstands idle for any considerable period the ignited fuel may cool belowincandescence so that it may be necessary to blow in the fuel bed afreshbefore good combustible gas in quantities may be secured. This may makenecessary a wait of several minutes before suitable gas is secured, andwould also make necessary igniting kindling material in the produceritself. In order that the fuel bed may be at all times maintained insuitable condition, even during considerable stand-by periods, means isprovided whereby the blower is automatically operated at intervals tocause a short blowing in of the fuel, bed to maintain it alight, thispermitting remote control at all times. This means is shown in Figs. 5and 6 in which the control mechanism is provided with a second electrode200, which is similar to the electrode but is of somewhat less length.In order to enclose these two electrodes a double tube 201 is providedwhich has two depending legs, one which contains the electrode 95 andthe other designated by the numeral 202 which houses the additionalelectrode 200. The upper ends of these two tubes are connected to themain body of the tube 201 by means of cement, or the like, as is shownin Fig. 5

the drawing, for example. TherV is also positioned within the ieg 200 ofthe main tube a second tube 2023 which extends down below the normalstand-by level of the electrolyte and the in..

lterior of which is disconnected from the interior of the main body ofthe tube when its lower end is within the electrolyte. This tube 203 hasa branch 204 extending to the outside of the main tube` 201, withinwhich is positioned a closure member having a predetermined orificetherethrough, the orice member being designated by the numeral 205. Thisorice member may be of any suitable character; but in practice a smallpiece of thermometer tubing functions very satisfactorily. The main partof the tube 201 is connectecl by means of passage 115 to the gaspressure within the valve casing as described above. During operationthe tube 201 with its two depending legs 100 and 202 will be so filledwith gas that the level of the electrolyte is at approximately the lowerend of the electrode 95. But when the plant is shut down or standing bythe electrolyte rises within the legs 100 and 202 until it is atsubstantially the same level inside and outside thereof; except that asthe electrolyte covers the lower end of tube 203 it traps gas thereinand can rise in that tube only as the trapped gas escapes through theorice in the member 205. And the effectivey area of that orice is suchthat after a predetermined interval the gas will have escapedsufficiently to permit the electrolyte to move upwardly in the tube 203to contact with the electrode 200. This electrode 200 is connected bymeans of a conductor 210 with the line 91 which is a circuit shuntedaround the main motor circuit contacts 92-93, this arrangement beingsuoh that as the electrolyte contac-ts with electrode 200 the motor isenergized to start the blower to cause blowing in of the fuel bed. Butthe motor will run for only a brief period as its operation builds uppressure within the main tube 201, which breaks the contact. Thisblowing in period may be of such length as desired but ordinarily isjust sufficient to liven up the fuel bed and keep it alight. Theintervals between these periodic blastings will depend on the timenecessary for the gas leakage from the tube 203 to permit closing of theoy-pass circuitand this depends on the size of the tube 203, the extentof necessary electrolyte rise therein, and the effective area of theorifice. In actual practice satisfactory results have been secured wherethese blastings occur at about ve minute intervals; but the intervalsbetween them may be regulated to suit operating conditions. Because ofthe normal stand-by positioning of the valve 60 the gas resulting fromsuch periodical blasting will be discharged to vent.

In Fig. 7 is shown, diagrammatically, a modification which gives thesame results as does the.

form of Figs. 5 and 6; but which is simpler in construction. In thisgure a single large tube 225 is provided which is suitably supportedfrom the cover 226, in gas-tight relation as is the case also in theother forms shown and described above. Extending down through the cover226 and into the space within the tube 225 is a second tube 227, whichis connected by means of the passage 115 to the outlet of the blower, asdescribed above. Mounted in the cover 226 and extending down differentdistances into the space between the two tubes 225 and 22'? are twoelectrodes 95 and 200. Also mounted in the cover 226 is a leak tube 204having an oriiice member 205. The operation and function of theseseveral elements are the same as described above. In Fig. 7 the level ofthe electrolyte is shown as of immediately after stopping the blower andbefore any appreciable leakage of gas through the leak tube 204. In Fig.6 the level of the electrolyte is shown of a time when the leakagethrough tube 204 has just permitted the electrolyte to contact with theelectrode 200 to close the motor bypass circuit. In Figs. l, 2, and 5the level of the electrolyte is shown as of stand-by period with thelevels inside and outside the tube 100 the same.

While the forms of apparatus herein described constitute preferredembodiments of the invention, it is to be understood that the inventionis not limited to these precise forms of apparatus, and that changes maybe made in either without departing from the scope of the inventionwhich is defined in the appended claims.

What is claimed is:

l, Electrolytic switch mechanism comprising a container, an electrolytetherein, an electrode normally immersed in said electrolyte, a secondelectrode extending into the container, a third electrode extending intothe container and terminating above the lower end of said secondelectrode, a tube closed at its upper end surrounding said second andthird electrodes and extending down into the liquid and having anopening below the liquid level, means for connecting the interior ofsaid tube above the open portion thereof to a pressure source, and arestricted outlet providing a slow leak for the pressure space of saidtube.

2. Electrolytic switch mechanism comprising a vessel adapted to containan electrolyte, spaced contact members within said vessel normallyimmersed in the electrolyte, an inverted container closed at the toppositioned about one of said contact members and having an open portionbeneath the normal level of the electrolyte, and means for connectingthe interior of said conn tainer above the open portion to a uidpressure source, so that upon a predetermined increase in pressurewithin the container above that existing within the said vessel on theexterior of the container, the electrolyte is depressed within saidcontainer below the end of said one contact member therein.

3. Electrolytic switch mechanism comprising a container, an electrolytetherein, an electrode normally immersed in said electrolyte, a secondelectrode extending into the container, the lower end of said secondelectrode terminating in a flat face, a tube closed at the topsurrounding said second electrode and having an opening below the normallevel of the electrolyte and below the fiat face of said electrode, andiiuid pressure means effective upon the electrolyte within said tube tocause its level to rise and fall with its surface substantially parallelwith the 'dat face of the lower end of said electrode into and out ofcontact with said flat face, whereby the surface tension of theelectrolyte cooperating with the flat face of said electrode produces anecking down eifect as the level of the electrolyte moves below the iiatface of said second electrode.

fi. Switch mechanism for an electrical circuit, comprising switchcontacts in said electrical circuit, fluid pressure means communicatingwith a fluid pressure source for opening and closing said contactswithin a predetermined pressure range, a second pair of switch contactsin said electrical circuit in series with said first mentioned switchcontacts, a second fluid pressure means also communicating with said uidpressure source for holding said second pair of switch contacts closedwithin the said predetermined pressure range of opening and closing ofsaid first mentioned contacts, said second fluid pressure meansoperating at a different predetermined pressure range to release theholding of said second pair of switch contacts, and means for openingsaid second pair of switch contacts upon said release of the holdingthereof.

5. Switch mechanism for an electrical circuit, comprising a pair ofcooperating switch contacts in said electrical circuit, fluid pressuremeans communicating with a fluid pressure source for opening and closingsaid contacts within a predetermined pressure range, a master controlswitch for said circuit in series with said pair of switch contacts, asecond pair of cooperating switch contacts in said electrical circuitshunted around-said first mentioned pair and shunted around said mastercontrol switch, said second pair of contacts being actuated by fluidpressure from said fluid pressure source but at a diiferentpredetermined pressure range to automatically close said circuitintermittently and for short periods when said master control switch isopen.

HARRY F. SMITH.

